An estimated 85,000 runners left Sydney's Hyde Park at 8am on their way to Bondi Beach for the Sun-Herald City2Surf presented by Westpac.
Among them were ballerinas, pandas and even the man hoping to be the next prime minister.
Ben Moreau, 31, from Woolloomooloo, won the race on his second attempt.
Moreau, who finished sixth in his first City2Surf last year, said a mid-course surge determined the outcome. He won the 14km race in 41:47.
"Those little sharp hills after Heartbreak Hill were the hardest," he said. Linda Spencer, 31, from Western Australia was the first woman, crossing the finishing line in 48:28.
Liam Adams, 26 from Melbourne, failed to take a third win this year. He said Heartbreak Hill was "the killer"."I lacked the top-end speed and the hill work," he said.
The competitors were led out about 8am by wheelchair racers led by Paralympic legend Kurt Fearnley, who won the wheelchair category with a time of 34:10.
"This is what living life is about. I've had a ball," the 32-year-old said. "It's a beautiful atmosphere in a beautiful city."
Opposition Leader Tony Abbott also competed in the iconic race alongside vision-impaired athlete Nathan Johnstone.
Mr Abbott will then travel to Canberra on Sunday afternoon to face off against Prime Minister Kevin Rudd in the first leaders' debate at the National Press Club.
"You've always got to be of the right frame of mind for a debate,'' Mr Abbott told Fairfax Media. "A run or a ride is terrific preparation.''
Race organisers said Sunday's crowd was expected to equal the race record.
Frank Pigott, a 63-year-old veteran runner, said he was hoping to beat his age.
That would be a long way off his personal best time of 54 minutes - but in his 26th City2Surf, he said he would be happy to beat last year's time.
The event hopes to raise $4 million dollars for charity this year.
Londoner Adrian Downer has made competing part of his yearly holiday.
"It's a hell of an event," he said. "I mean, it's the biggest in the world."